The present invention relates to a device for carrying out mechanical tasks, in particular pressing, riveting, folding and cutting, on components by means of tool elements arranged on a substantially one-piece, approximately C-shaped tool holder defining an operating region in such a way that during operating between the tool elements the components can be positioned at least partially in the operating region. The tasks can be done hydraulically, pneumatically, electrically or in combination with one another.
A generic device, in this case for connecting in one working process two or more elements formed from metal sheets located on top of one another, is known, for example, from U.S. Pat. No. 5,425,262. At least one stroke or a movement along a pre-determined path is carried out by at least one active tool element towards a tool element cooperating with it. The tool elements are arranged respectively on a tool holder and form first and second tool holders with a defined operating region in between. During the working process, the elements to be connected to one another, formed from sheet metal, are positioned in the operating region, i.e. between the tool elements. The first and second tool holders can be moved towards one another in a rotational movement round a rotational connection in a first part of the stroke mentioned. Additionally the device has a locking mechanism which locks the rotational movement between the first and the second tool holders at the end of the first part of the stroke. The rotational connection is arranged in a position near the centre of gravity of one of the two tool holders between a line through the active and cooperating tool elements on the one hand and the locking mechanism on the other hand.
The arrangement of the rotational connection near the centre of gravity has the advantage that no otherwise arising moment forces have to be taken into consideration, in particular balanced. An arrangement of this kind has the disadvantage, though, that the operating region has to be kept relatively small with respect to its insertion depth for the components if one does not wish to create correspondingly voluminously dimensioned and thus relatively heavy devices which at the same time have to accommodate very high forces, for example during a connecting process.
It is the object of the present invention to make available a relatively light, preferably hand-operated, compact device for carrying out mechanical tasks, in particular pressing, riveting, folding and cutting, on components, with an operating region which also allows tasks at a greater insertion depth on components. In particular it is to be ensured that the device remains upright in any chosen working position almost without force.
In the device according to the invention for carrying out tasks on components by means of tool elements arranged on a substantially one-piece, approximately C-shaped tool holder defining an operating region in such a way that during operating between the tool elements the components can be positioned at least partially in the operating region, the tool holder is held via a first rotational connection as vertically pivotal in a mount, and the first rotational connection is arranged in a position at a significant distance from the centre of gravity of the tool holder, wherein at least one holding element is provided for an approximate balance of moments arising as a result of the positioning of the first connection at a distance from the centre of gravity into different positions of the tool holder.
The significant distancing of the first rotational connection from the centre of gravity has in particular the advantage that an operating region can be formed with a large insertion depth for the components, so, in an advantageous manner, tasks can also be carried out at a correspondingly larger depth on components, which otherwise could not be carried out by means of a generic device.
Owing to the fact that a holding element is provided, by means of which the moments arising because of the positioning of the first rotational connection at a distance from the centre of gravity can be approximately balanced in different positions of the tool holder, very accurate positioning of the device is made possible. Furthermore, the holding element ensures that no, or only very slight, moments are passed into holding devices of the devices when the device is pivoted round the rotational connection. This is of particular advantage if the device is arranged on an arm of a robot or a robotal device. There is therefore no need for additional measures on the robot arm or the robotal device to compensate for the moments caused by pivoting of the device.
The device according to the invention is also suitable for hand-activated use. With a relatively small expenditure of force the operator of the device can pivot the tool holder into pre-determined positions.
It is preferred according to the invention that the distance between the first rotational connection and the centre of gravity is greater than 5 cm and, preferably, at least 15 cm.
According to an advantageous configuration of the device it is proposed that the holding element is formed by at least one spring element. This achieves a reliable and safe configuration of the holding element.
If the first rotational connection and the centre of gravity lie in a common vertical line the spring element is preferably biased.
The spring element is preferably biased at a maximum force. In a resting position the force vector of the spring element points at the rotational point, so the moment constituted by the spring element is almost zero. The moment necessary for the rotation of the tool holder rises sinusoidally and reaches a maximum when the tool holder is rotated round an angle of 90xc2x0. The lifting arm, by means of which the spring element generates a rotational moment, which can also be designated as a re-adjusting moment, becomes sinusoidally larger. The spring force of the spring element is reduced to about 80% of the maximum force during rotation round 90xc2x0. Because the lifting arm is getting larger during pivoting of the tool holder, the moment necessary for pivoting the tool holder is reduced.
If, however, the tool holder is vertically pivoted, for example by hand, the spring element tenses and generates a moment which is approximately equal to the moment arising because of the positioning of the first rotational connection at a distance from the centre of gravity as a result of gravitational force.
This ensures in an advantageous manner that the device remains upright in any chosen working position almost without force.
It has been found that a particularly good moment balance is produced if the spring element is arranged between mount and tool holder.
It is preferred according to the invention that the spring element is a gas pressure spring. Other suitable spring elements can also be used.
In order to achieve working positions beyond the vertical pivoting region too, it is proposed that the mount is held via a second rotational connection on a holding device and pivotally round an axis located in the horizontal line.
In order to be able to control working positions in a three-dimensional space it is proposed to hold the holding device pivotally round an axis located in the vertical line.
It is preferred according to the invention that the device is made in such a way that it can be operated by hand. For this purpose at least one handle region, preferably at least two handle regions, is formed on the tool holder.
The device according to the invention for carrying out tasks on components is characterised by its great ease of handling, which is additionally improved in that the device can, on the whole, be designed as very slim.